In recent years, there have been occasional news reports of people being poisoned by eating wild mushrooms. People may have the wrong idea that poisonous mushrooms are always brightly coloured and it will be safe if these are avoided. However, there are many poisonous mushrooms that are ordinarily white or brown in colour.
Worldwide, there are tens of thousands of mushroom species, some 200 of which are known to be poisonous. Although the percentage is low, the huge number and variations make it extremely difficult to identify the inedible ones simply by colour and form — particularly as some inedible and edible species look very similar. Even when it is an edible species, it should not be taken from the wild and eaten, as wild mushrooms are easily infected by viruses, moulds, bacteria and pests. Furthermore, if pesticides and herbicides have been applied in the surrounding environment, or the soil has been polluted by heavy metals, these pollutants will stay in the mushrooms.
Similarly risky is the recent fashion of cultivating mushroom at home. For one, it is different to cultivate mushrooms and other plants or crops. In addition, mushrooms are more vulnerable than common plants to infection, and the symptoms may not be easily spotted. Although a domestic environment may look clean, invisible viruses and bacteria may still infect the mushrooms.
The mushrooms we usually consume come from artificial cultivation under a “germless” environment with temperature, moisture, humidity, oxygen level, light intensity and pH all strictly controlled. For safety, do not consume mushrooms you have cultivated or collected in the wild or with unknown sources.